Lighting is an important part of everyday life. Since the time that light bulbs were invented in 1879, light bulbs have had a significant effect on human activity by providing illumination in areas and at times that would not otherwise allow such activities. One of the goals of developing lighting technologies is to meet desired illumination requirements for various activities in various venues, such as homes, offices, restaurants, etc., and for various purposes, including utility and decorative purposes.
Light emitting diodes (LEDs) are semiconductor diodes that belong to the group of electroluminescent luminaries. Photons are emitted from LEDs by recombining charge-carrier pairs in a semiconductor with an appropriate energy band gap. As a result, LEDs provide narrow bands of radiation. LEDs constitute desirable sources of lighting because they operate at low voltage and power, are small and have an extended lifetime and stability.